1. Area of the Invention
This invention relates to load beam/flexure assemblies for Winchester disk drives which are used for supporting magnetic read/write heads adjacent to the rotating disks. More particularly, this invention relates to such load beam/flexure assemblies for mini-composite and mini-monolithic Winchester disk drives (hereinafter referred to as "mini Winchester disk drives").
2. Description of the Prior Art
Mini Winchester disk drives have a plurality of flat, circular spaced apart disks 12 (FIG. 1) rotating about a common spindle (not shown). In typical mini Winchester disk drives, the disk-to-disk spacing (S.sub.DD) is 300 thousandths of an inch, (hereinafter 300 mils).
The data is stored in the magnetic media formed on the surface of the disks Typically, the data is divided into groupings called tracks that are concentric rings similar to the annular growth rings on a tree. In most Winchester disk drives, the concentric rings are on both sides of the disk. A magnetic read/write head is positioned above each side of the disk. As the disk is spun beneath the head, the read/write head can magnetize the magnetic media in the track, thereby writing onto the track. After data is stored on the track, the read/write head can be positioned above a track and, as the disk spins, the read/write head can read the magnetic pattern stored on the disk in the track. To write onto or read from different tracks, the read/write head merely needs to be moved towards or away from the spindle
A read/write element (not shown) for each disk is positioned immediately adjacent to each flat surface of the disk 12a and 12b as the disk spins beneath it. The read/write element is mounted on a slider 16 which has an air bearing surface positioned immediately adjacent to the flat surface of the disk. As the disk spins, the air following the disk applies pressure to the slider's air bearing surface and lifts the slider and the read/write element off of the surface of the disk.
Positioning the slider body over the disk is accomplished by attaching the slider body to a component called a flexure 14. The flexure 14 allows the slider body to gimbal for pitch, roll and transverse motion, but restricts the slider's motion in the radial and circumferential directions of the disk. To support the flexure 14 in the proper position, each flexure is attached to an elongated load beam 20, which is in turn attached to an arm 30 coupled to the carriage 38 of the Winchester disk drive. The portion of the flexure 14 that is attached to the slider 16 is called the tongue portion and the portion that is fastened to the load beam is called the body portion The load beam is generally made of steel and acts as a leaf spring to bias the slider 16 towards the disks.
Typically, each load beam 20 comprises an elongated, flat load beam base 24 with two side flanges 22 integral with and at the sides of the load beam base 24. One end of the load beam (the slider end 26) is coupled to the flexure while the other opposed end (the arm end 28) is adapted for attaching the beam 20 to the arm 30. The slider end 26 has a fork-like structure called a split finger 29 that projects above the side flanges 22. This split finger 29 is used for holding a wire tube (not shown) in place against the top surface of the load beam base 24. The wire tube contains the wires that connect the read/write head (not shown) to the read/write circuitry of the Winchester disk drive.
Usually the load beam 20 is attached to the arm 30 via a flat insert 32. The flat arm end 28 of the load beam is welded to the insert 32. The insert is then bolted to the arm by a bolt 36 with the insert 32 positioned between the arm end 28 of the load beam and the arm 30. Typically, the arm 30 is then attached to the carriage 38 of the Winchester disk drive via a bolt 40. The arms with the load beams attached form an interdigitated structure as seen in FIG. 1.
It is important that the air bearing surface of the slider 16 be substantially parallel to the disk surface. In prior art devices, the tongue portion of the flexure 14 is at approximately a 2.degree. 20' the base 24 of the load beam. To compensate for this 2.degree. 20' angle, when the load beam/flexure assembly is mounted in the disk drive, the angle between the surface of the arm 30 and the base 24 of the load beam 20 is also 2.degree. 20'. The two 2.degree. 20' angles may be thought of as interior, corresponding angles formed by the "parallel lines" of the surface of the arm 30 and the disk surface (12a or 12b) and with the load beam 20 being the transversal. Thus, the slider's 16 air bearing is substantially parallel to the surface of the disk.
Furthermore, in such prior art mini Winchester disk drives, when the load beam/flexure assemblies are inserted into the drive, there must be sufficient clearance between the adjacently positioned sliders 16 and the disk 12 and the adjacently positioned load beams such as 20a and 20b. If there is any interference between sliders and disks during assembly, damage will be likely to occur. Typically in the prior art, adequate clearance has been accomplished by keeping a spacing between adjacent disks (S.sub.DD) at about 300 mils. However, this relatively large disk to disk spacing (S.sub.DD) frustrates efforts to reduce the total size of the mini Winchester disk drive.
A further consideration in the prior art is that it is sometimes necessary to remove a particular load beam/flexure assembly for repairing or replacing the Winchester disk drive. Usually, bolts 40 and 36 are used to allow for assembly and disassembly. A disadvantage of using these bolts 36 is that the bolts 36 are so small that it is easy to strip a thread on the bolt in the mating hole or not adequately clamp the load beam 20 to the arm 30. Furthermore, these bolts 36 and the tapped mating holes are quite expensive.
Not only are the bolts 36 costly, but machining the carriage 38 and the arms 30 so the arms will be precisely positioned is expensive. The machining operation may contribute as much as about one third of the overall cost of the carriage. Also, the number of parts required in this structure increases the overall cost.
Furthermore, if it is necessary to remove one of the read/write heads for repairs, the load beam to which the head is attached cannot be removed without first removing the arm. The arm must be removed because the bolts 36 are not accessible in the assembled drive. Thus, the entire arm 30 must be unbolted from the carriage 38. Furthermore, each of the wires of all of the heads must be disconnected from the read/write circuitry of the Winchester disk drive. Since as many as four heads may be attached to an arm, being required to disconnect all of the wires for each head when only one head needs to be repaired is highly undesirable.
Thus, it is an object of this invention to provide for a compact mini Winchester disk drive structure. It is a further object of this invention to have such mini Winchester disk drive have load beams that are easily removable and reattachable while eliminating the attachment bolts.